1. Field of the Invention
This invention relates generally to circuit breakers and, more particularly, to circuit breakers of the electromagnetic type including an operating mechanism and an operating handle.
2. Background Information
Circuit breakers of the electromagnetic type are shown, for example, in U.S. Pat. Nos. 3,329,913, and 4,151,386.
Such electromagnetic circuit breakers typically comprise an operating mechanism including a frame, a movable contact, which is mounted on a movable arm, and a fixed or stationary contact. An operating handle is coupled to the movable arm via a linkage mechanism, part of which comprises a collapsible toggle assembly. The movable and stationary contacts are operated between contacts xe2x80x9copenxe2x80x9d and contacts xe2x80x9cclosedxe2x80x9d positions by pivoting the operating handle. The circuit breaker further comprises an electromagnetic device which, in response to one or more predetermined electrical conditions, collapses the toggle assembly to a broken state, in order to electrically trip xe2x80x9copenxe2x80x9d the separable movable and stationary contacts.
In some circuit breakers, the movable arm is connected by a pin to the linkage mechanism, which includes a catch link and a U-link. The catch link is, in turn, connected to an internal extension of the operating handle by a pin. Such circuit breakers employ a stop, in order to prevent the operating mechanism from swinging through its intended travel and pulling the movable contact off the stationary contact at the closed position. The handle stop includes an extension of the frame, which extension engages an end of the operating handle/toggle catch link pin, in order to prevent further travel of the operating handle and, thus, further travel of the handle internal extension, the linkage mechanism, the movable arm and the movable contact.
There is room for improvement in circuit breakers.
These needs and others are met by the present invention, which provides a tab or stop disposed from the base of a frame to stop one or two independent links in the closed position of the circuit breaker. As these links swing through their movement they contact the tab on its tip and stop. This establishes the ideal position of the operating mechanism and the movable contact arm, in order to position the movable contact with respect to the stationary contact in the closed position. This allows the separable contacts to remain closed and, also, keeps the desired contact force of the operating mechanism.
As one aspect of the invention, a circuit breaker comprises: a case; a frame fixedly disposed within the case, the frame including a stop; separable contacts; and an operating mechanism for opening and closing the separable contacts, the operating mechanism including an operating handle, a closed position, an open position, a linkage having a first end and a second end, and a link pivotally mounted to the case and to the first end of the linkage, the stop of the frame engaging and stopping movement of the link in the closed position.
The frame may include a base and two parallel sides, with the stop attached to the base and being disposed between the parallel sides.
The operating handle may include a pair of elongated arms within the case, the elongated arms being disposed between the parallel sides of the frame, and the stop and the link being disposed between the elongated arms. The operating mechanism may further include a pair of extension springs and a pivot between the link and the first end of the linkage, with each one of the extension springs extending between a corresponding one of the elongated arms and the pivot.
The linkage may include a protrusion, and the stop may engage the protrusion of the linkage and stop movement of the linkage in the open position.
As another aspect of the invention, a circuit breaker comprises: a case; a frame fixedly disposed within the case, the frame including a tab; separable contacts; and an operating mechanism for opening and closing the separable contacts, the operating mechanism including an operating handle, a closed position, an open position, a first link having a first end and a second end, a second link pivotally mounted to the second end of the first link, and a third link pivotally mounted to the case and to the first end of the first link, the tab of the frame engaging and stopping movement of the third link in the closed position.
The frame may include a base and two parallel sides, with the tab disposed from the base and between the parallel sides.
The operating handle may include a pair of elongated arms within the case, the elongated arms being disposed between the parallel sides of the frame, and the tab and the third link being disposed between the elongated arms.
The operating mechanism may further include a pair of extension springs and a pivot between the third link and the first end of the first link, with each one of the extension springs extending between a corresponding one of the elongated arms and the pivot.
The second link may include a protrusion, and the tab may engage the protrusion of the second link and stop movement of the second link in the open position.